The textile industry has a large use of synthetic dyes. The synthetic dyes are mostly used because of their ease and cost-effectiveness. But the disadvantage of synthetic dyes are often toxin, mutagenic and carcinogenic, leading to several human health problems. Because of these properties of synthetic dyes, the demand for naturals dyes in textile industry was increasing. Therefore, the naturals are extracted from plants such as Indian madder, woad and weld yielding red, indigo and yellow dyes.
But, there are also disadvantages in using the plants for the production of natural dye. The disadvantage of using plants are production of large amount of biomass, destruction of species on a large scale, color production is season dependent and practically low color yields.
To overcome these drawbacks, fermentation of microorganisms such as bacteria and fungi can be used as a source for production of natural dyes. Microorganisms produces a numerous stable pigments, and it has higher yield and lower residues than plants.
The microorganisms such as Serratia sakuensis produces red prodiogiosin pigment, Jantinobacterium lividum and chromobacterium sp produces violet pigments, Ashby produces yellow riboflavin and fusarium oxysporum produces anthraxquinones .
This paper mainly describes about the red pigment known as prodigiosin produced by the bacterium Serratia marcescens. The red pigment is a natural dye and used for dying natural fabrics in textile industry.
The pigment prodigiosin produced by bacteria serratia marcescens has many applications such as dyeing, antibacterial and antifungal activity.
Prodigiosin production was usually done in nutrient broth and peptone glycerol broth. Nutrient broth is used for the pigment production as it is basically devoid of carbon source; it is also associated with yeast extract and maltose. The peanut medium is also used for the prodigiosin production. It serves as the best medium. It severs as the best medium.
Carbon source plays a vital role in production of prodigiosin pigment. It was reported that the bacterium produce higher amount of prodigiosin at 300c and at pH 7. It was found that the pH and temperature increases more than 300c at pH 7 the amount of pigment production was decreased. In another study, prodigiosin pigment production found to be stopped up at 370c. Mordants are applied on the textile fabrics to gain altering colors and to enhance the dye uptake, to get better the color fastness performance of several natural dyes.
Many types of mordants used on the natural dye may darken, make brighter or significantly modify the color of the dye mordant solution and control the darkness of the final product, which may be a required effect or an unwanted occurrence. The fading of colored textiles upon exposure to light is a well known phenomenon.
The rose-red color pigment obtained from the Serratia marcescens can be used as a natural dye for dyeing silk, wool and cotton fabrics for pink color. However, the fastness properties being moderate, the future studies on either pretreatment of the fabrics or chemical modification of the microbial pigment to improve the fastness properties performance can be undertaken. In the large scale production, the pigment will be make it an alternating to chemical dyes.
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